// Copyright (c) 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef NET_QUIC_CRYPTO_CURVE25519_KEY_EXCHANGE_H_
#define NET_QUIC_CRYPTO_CURVE25519_KEY_EXCHANGE_H_

#include <stdint.h>

#include <string>

#include "base/compiler_specific.h"
#include "base/strings/string_piece.h"
#include "net/base/net_export.h"
#include "net/quic/crypto/key_exchange.h"

namespace net {

class QuicRandom;

// Curve25519KeyExchange implements a KeyExchange using elliptic-curve
// Diffie-Hellman on curve25519. See http://cr.yp.to/ecdh.html
class NET_EXPORT_PRIVATE Curve25519KeyExchange : public KeyExchange {
public:
    ~Curve25519KeyExchange() override;

    // New creates a new object from a private key. If the private key is
    // invalid, nullptr is returned.
    static Curve25519KeyExchange* New(base::StringPiece private_key);

    // NewPrivateKey returns a private key, generated from |rand|, suitable for
    // passing to |New|.
    static std::string NewPrivateKey(QuicRandom* rand);

    // KeyExchange interface.
    KeyExchange* NewKeyPair(QuicRandom* rand) const override;
    bool CalculateSharedKey(base::StringPiece peer_public_value,
        std::string* shared_key) const override;
    base::StringPiece public_value() const override;
    QuicTag tag() const override;

private:
    Curve25519KeyExchange();

    uint8_t private_key_[32];
    uint8_t public_key_[32];
};

} // namespace net

#endif // NET_QUIC_CRYPTO_CURVE25519_KEY_EXCHANGE_H_
